Several processes for preparing diaryl sulfones, such as 4,4′-dichlorodiphenylsulfone (DCDPS) are known. Such processes may utilize various paths to make diaryl sulfones starting various aryl starting materials, such as from chlorobenzene.
In one exemplary diaryl sulfone preparation described in U.S. Pat. No. 4,937,387, DCDPS is produced from sulfur trioxide and monochlorobenzene in a two-step process. The first step is the reaction of monochlorobenzene with sulfur trioxide to form chlorobenzene sulfonic acid (CBSA). The second step is the reaction of chlorobenzene sulfonic acid with monochlorobenzene. The reaction in reported to result in an average conversion to DCDPS of 20.8% based on CBSA and sulfuric acid feed (Table I). Additional steps are taken to recover unreacted CBSA for repeating the second step to form additional DCDPS.
